The present invention relates to an electronic cash register.
In an electronic cash register, various data associated with the cash registration are stored in a volatile memory that requires the constant supply of electric power. In order that data to be registered for a predetermined period of time, for example, for several days, is stored in the volatile memory, the memory must be powered by electricity even when the cash register is not operated. In the event that the commercial electric power supply is interrupted for any reason, the volatile memory is powered by an auxiliary back-up power source, for example, a battery, to protect the once-stored data from being volatilized.
Since any battery used for the back-up power source for continuously powering the volatile memory has a limited lifetime, and/or for any other reason, it may happen that the volatile memory will no longer be powered. Thus, according to the prior art, there is a problem in that the reliability of the data stored in the volatile memory for a long period of time is not very high.